So after getting 2 replacement sets of strings from Rotosound after emailing them, I've tried the first set of the 2 they sent me, and damn, 2 dead strings fresh out of the pack! This time it's the E string and A string, the D and G sound like they should, which sucks cause each string sounds vastly different from one another. These were the Swing Bass 66 RS66LDN pure nickel roundwounds. I've switched back to Fender's pure nickel roundwounds (7150M I believe) because so far from every set of them I've got, each and every string sounds new and alive like any new string should, and all 4 strings in the set sound uniform to each other. I really, really hope Rotosound picks up their quality control some day, but for now I just can't afford to buy sets of strings that I have no way of being sure won't have duds in them. So far in the past year every single pack of Rotosound Swing Bass 66 pure nickels have had 1 or 2 duds in each and every pack I've installed, and I am installing them correctly. It's worth noting that in years past and still on my spare bass I've used their Roto Bass nickel plated steel Roundwounds and have never had an issue. But as far as pure nickel roundwounds, which are my preferred string material for my main (Jazz) bass, the Fender strings are far better than the Rotosounds, in terms of every single string sounding new, each string sounding the same as the other strings in the set, tone (even the Rotosounds which came out of the pack alive and sounding new didn't compare to the Fenders when new) and also how long they last, the Fender strings seem to last me 2-3 times as long before they get dull enough that I want to change them (I do change strings fairly often, I like the sound/feel of newer strings.)